Improved engine for operating rock-drills



UNITED STATES JAMES D. BUTLER, OF NORTH ADAMlMASSACHUSETTS.

IMPROVED ENGINE FOR OPERATING RCK-DRILLS.

Spccilication forming part of' Letters Patent No. 17,399. dated April 25, 1865.

To @ZZ whom it may concern: g

Be it known that l, JAMES D. BUTLER, of' North Adams, in the county of Berkshire and State of Massachusetts, have made an invention having reference to roclrdrilling engines to be worked by compressed air, steam, or gas; and I do hereby declare the same to be fully described in the following specification and represented in the accompanyin g drawings.

The engine is of the class in which the drill, by means of a reciprocating piston, is alternately thrown against and withdrawn from the rock to be drilled.

The machine is represented as adapted lor the use of compressed air, which by means of a conduit is to be led into it from the reservoir in which such air may be confined.

In the accoinpanyingdrawings, Figure l represents a longitudinal section of the machine; F1g.2, a side elevation, and Fig. 3 an end View, ot it. Fig. 4 is an end view of its cylindercover, piston-rods, &c. Fig. 5 is an end view ot' its cross-head and slides. Fig. 6 is a transverse section taken through the line 0 0 of Fig. 2. Figs. 7 and S are detailed views of the annular packing-segments; and Figs. t). 1t), and ll represent detailed projections of the spring catch and attachments for the mainvalve stem.

In Figs. 1,18, 4, 5, and 6, Arepresents the engine-cylinder,havingwithinitapistonhead, 13,1rom opposite ends of which two tubular pistoni-ods, U D, are projected through the heads ofthe cylinder. Within the hollow rod U is an auxiliary piston, E, from which runs a tubular piston-rod, F, which goes axially within the hollow rod D and through another piston, Gr, to which it is fastened, a nut, H, be-

- ing screwed on such piston-rod F. A hollow cone, l, arranged on the rod F, bears against the nut H. There is a packing box, bi, around the piston-rod F, and in the main piston B. The rod F has lateral openings made through it for reception of certain gibs J J, which are arranged as shown in Figs. 1, 3, and 4. The piston G works in a short cylinder, K, which is fastened to the hollow piston-rod D, and by means of such rod is also connected to the main piston B. A hollow cone, L, surrounding the gibs J J, is lixed to the end of the cylinder K and arranged relatively thereto, as represented in Fig. 1.

In order to prevent the two cones I L from revolving about their axis with reference to each other, the two gibs J J may beextended a short distance into grooves made in such cones. The piston G and its rod F should be kept from revolving in the cylinder K and rod B by means of pins lc k, extended from the cylinder and into slots q g made in the piston G. Upon the exterior of the cone I is a spring, M, which takes into one of a series, 7L, made in the nut H, as shown in Figs. 1, 3, and 4. In the piston-rod D a-re holes d, opening into the annular space between the rods D and F. In

the piston-rod O there are holes c c', opening into the annular space between the rods or tubes C and F. y

N is a drill which passes between the gibs J J, and also through the rods O and F, and a collar, Q', carried by across-head, Q. The two points or places of support of the said drill are between the gibs and the cross-head collar. ln the collar the drill bears at two opposite corners, q', (see Fig. 5,) the other two being somewhat cut away to allow the wings n of the cutting-edge ot' the drill to pass through it from the farther end ofthe machine at which the drill is inserted. The gibs J, when the (vngine is in operation, open and close alternately upon the drill, forming, when closed so tightly upon it that it shall not slip between them, a connection between the main piston-head and the drill, through the cone L, the cylinder K, and the piston-rod D, that the drill shall partake of the motion of the piston-head. The cylinder A, from a to a', is reduced in diameter of bore, and there receives a part, b b', ot' the main piston which iits to it. The cylindercover A is hollowed out at X to a diameter less than that of the main part of the cylinder, and to the proper depth, ata, the end b b of the main piston being turned down to lit into the space X. l

In the cylinder-head A is the packingbox for the piston-rod (l. 'l'here are two pieces or rings of leather or other suitable material, pp and p p, each in the shape of a ring, with one portion turned over to form a sort of flan ge. They encompass the piston-rod, and have between their anged ends another piece of leather or suitable material, p4, which bears against the outershell, A", of the packingbox. Each of the leather rings is supported by sets of wedges or segments of one of two conical rings, P P', one of which is fully shown in Figs. 7 and 8. rIhese segments are placed within hollow cones, one of which isv 1n -the packing-box proper, and the other inthe follower A. The bringing up of the follower upon the packing-box acts through the seg- .and on the paekin g p4, between these flanges,

forcing it out against the shell and making the box tight all around. The packing p4 is introduced to prevent leakage around the outside of the segments. The segments are set with smallspaces p5, (see Figs. 7 and 8,) between their ends, such spaces bein g necessary in order to allow the contractionofl the segmentsinto a smaller circle as the packing is set up. As they are represented, the holes in the cylinder-cover and in the follower for reception oi' the piston-rod O are formed considerably larger in diameter than that ofthe said pistonrod. Thus the rod will be guided by the packing simply. It may be thought best to have the said holes so made that their sides shall be in contact with the rod throughout the whole circumference, or in spaces at regular intervalsou it, so that the rod may be guided by the holes or parts thereof. The other piston-rods may be packed in the same way as the above, or all may be packed in any ofthe known ways. The outer end of thepistonrod, C, is brought up against the crosshead Q., and kept there by three screws, o, (see Figs. l and 5,) which screw into the rod, and project in rear of a shoulder, q, of the crosshead.

By inspection of Fig. 1 it will be seen that the part of the cross-head which projects into the piston-rod has a diameter somewhat less than that of the bore of the rod; also, that the inner ends of the screws c do not touch the cross-head, so that there is alf liwed a free transverse motion between the pistonrod and cross-head, while yet no motion is permitted in the direction ot' thelength of the piston, and the cross-head is kept perpendicular to the axis of the rod. The part ofthe cross-head to which the attachment of the piston-rod is made being cylindrical, a freedom of motion between the two about the axis of the rod isalso secured. The crosshcad runs upon guides Q, attached firmly to the main cylinder of the engine. The collar Qits'in the cross-head, but is free to turn init.

V is a valve-stem (see Figs. 1, 2, 3, 9, 10, and Il) which has in it a pin, U, with a beveled end, as shown, projecting into the slot V in the slide-bar V. This slide-bar is attached at u to the cross-head or" the engine, and reciprocates with it. It is guided by the blocks S and T, moving between them. Across the valvestem U is put the yoke U, whose two arms are let into grooves in the stem where they embrace it. A spring, W, fastened at ze,

and to to the valve-chest bears upon thev yoke Uf. In the spring are two holes, w fw, into either of which the pin U on the valve-stem will enter. In the slide-bar Vis a ledge@` c, whosenpper surface is beveled to the same vangle as the yend of the pin U',

vthe same being as shown in Fig. 1I. Its outer edge is at a depth from the face U, less than that to which the longer side of the pin reaches, while its lower corner is at a depth just exceeding the length of the 1in sufficient to allow the proper clearance.

The hole for the admission of the compressed air to the machine is represented at R in Fig. 1. From this point there is a free passage to one end of the cylinder through the port r r, (see Fig. 3,) so that a constant pressure is exerted upon the end b5 b b b5 of the piston. The constant-pressure space in the cylinder with the piston in the position shown is represented by the blue tinting of Fig. 1. From It the passage lt runs into the valve chest It. In this chest is a common slide-valve, R, acting to alternately admit the compressed air from the chest into the port r', and thronghit into the cylinder and upon the end bA Il b I)l of the piston, and to discharge it through the exhaustpas'sage r and R into the atmosphere. lThe area of the end b4 b b b4 is made larger than that of the end b5 b b b5. The pressure upon the end of bf b b b5, being constant, will move the piston before it when there is no pressure upon b4 b 11 b4; but when pressure is exerted upon b4 b" [1f/b4 it will drive the piston before it in opposition to the constant pressure. The area of b4 1) b" b4 effective for the. moving of the piston is the difference between its full area, and that of b5 Z1 b b5. Thus by having a` constant pressure on one end of -the piston and an intermittent one on the larger opposite end a reciprocating motion is given.

In the working ofthe machine an intermittent rotary feed motion about its axis is given to the drill as has been usual in drillingengines heretofore used. The drill being held firmly at times by the gibs J, it is suttcient at these times to give to the piston and its attachments such a rotary motion as is required for the drill. This is accomplished by the ordinary means of a ratchet and pawl7 the ratchet used in this machine being fixed on the cylinder K.

In using the machine it is placed with the crosshead end toward the rock to be drilled. The points q2 of the slides may be set against the rock, so as to give a point of support for one end of the machine, while the other end may be held by chains or any convenient fastening.

When desired, the machine may be entirely supported by being bolted to a frame, which shall be brought np near to the face of the rock.

The machine may be set in any positionhorizontal, vertical, or oblique.

The machine being in place, the drill may be inserted from the end ot' the machine that is farther from the rock, through the gibs, the hollow piston-rods and the cross-head collar.

The nut H is turned nearly ott', so as to allow the cones to separate and the gibs to open widely, so that there may be abundant room for the drill to pass through easily. When the drill has been inserted, the nut is turned as far up as possible, thus tightening the gibs upon the drill. From this position it is to be turned back as much as may be thought best to allow alittle play between the gibs and conesa nd the loosening of the gibs upon the drill. The spring M is then snapped into one of the notches It, thus holding the nut in place and preventing it from turning and shaking ott' from the rod. As the cone I simply bears against the nut H without being attached to it and the hole in the cone through which the rod passes is considerably larger than the rod, the cone is allowed a free transverse motion within certain limits with ret'- erence to the rod.` The eii'ect of this arrangement is that. while the cone may be thrown to one side or the other through irregularity in the gibs, the rod is relieved from transverse strain, which would tend to cause wear in and leakage around the pistons G E, attached to it.

In the drawings the piston is represented near one end ot' a full stroke. rIhe edge ot'the drill is supposed to be againsttlie rock. The gibs are lying loosely between the hollow7 cones and upon the drill, so that the pistou will move along the drill without taking it with it. When, however, the edges c ot' the holel c pass the edge p otl the packing in the picking box,theeoinpressed airrushesthrough these holes into the annular space between U and F, and, acting upon the piston E, gives motion to it in the direction toward the crosshead, and through it to the rod F, the piston G, the nut H, and the cone I. This cone I being drawn toward the cone L, the gibs are crowded upon the drill, taking a rin hold upon it. The drill, being thus seized,takes the motion ot' the main piston by which it is withdrawn from the rock. rl`his lirm hold upon the drillcontinues until in the return-stroke the holes d in the piston-rod l) come through the packingbox in the cylinder-head into the cylinder, which is now tilled with the compressed air. Through these holes the air passes into the annular space between the rods D and F, and through it into the cylin. der K, acting upon the piston G. rIhis pis ton, it will be remembered, is connected through the tube F with the piston E, which is ot' a largerl area, and consequently takes a greater pressure. The pressure upon the two pistons being opposite, the effect ot' that upon G is to neutralize in part the action ot' that on E, whereby the grasp ot' the gibs upon the drill is somewhat eased. The piston E may be called the mainclutch piston and G the counterclutch piston.7 The light hold of the clutches upon the drill is maintained until the edges 0 of the holes c pass the edge 19 of the packing, when the compressed air esca-pes into the atmosphere and the pressure is taken from the piston E. The pressure on thepiston G is relieved with that on the main piston by the escape ot' the compressed` air throurh the i main valve into the atmosphere. The gibs now lie loosely ou the drill, moving with the piston on it until the edges ot the holes pass the edge ot the packing on the return stroke, as heretofore explained.

As thc machine keeps the same position with reference to the rock, itis necessary that the drill be fed along through the piston as the hole in the rock is deepened. `rlhis is accomplished by making the distance between the outer edges, c 0', of the holes in the`piston-rod less than the length p p" ot'the pack` ing. Now, as we have seen, the drill is released i'roin the reciprocating parts ofthe machine when in the outward stroke the edges 0 of the holes c pass the edge p'f of ther packing. It, on the return-stroke, it was seized by the clutches when these edges passed each other, it would be in the same position with reference to the reciprocating parts as when it was released. It is therefore evident that the motion which the reciprocating parts take beyond this point before seizing the drill is the measure of the feed ofthe drill for each stroke,and is equal to the excess of the length of the packing-box over the distance between the outer edges of the holes in the piston-rod. rlhis feed is made greater than the usual advance ot` the drill into the rock, and the dii-'terence is taken up by the slip of the clutches upon the drill before releasing their hold. In order that this slip may take place easily, and Wthereby the' reciprocating parts of the machine be relieved from the shock of the blow ot' the drill upon the rock, the grasp ot' the clutches upon the drill is eased just before the drill strikes by the use of the counter-clutch piston, as above explained. This easy grasp of the clutches upon the drill could otl course be se` and yet doubtful distance from the point at` which they were set to seize it, and thus an element ot' uncertainty be introduced, which l would be fatal to economical and efficient working. lt is also necessary that the drill should be firmly held when the motion of the main piston is`reversed at the end of the` stroke the farther from the rock, else the momentum ot the drill might cause it then to slip in the clutches, and thus another element ot' uncertainty be introduced. The light hold of the clutches which is needed to give the slip when the drill strikes is safe only when the drill has been 'withdrawn from the rock and fairly set in motion wit-hihe piston to Ward it. This'easy hold ofthe drill is better thin its full release, since in the latter case it would recoil to a greater or less distance.

In its working the drill has aI decided tendency to glance and change its lineot direction when striking upon the iaee of the rock obliquely, or upon a vein of quartz, or upon any stratum ot a greater or less degree of hardness than the body oi' the rock. In the guiding ofthe drill, therefore, considerable strain is likely to be thrown upon its points of support in the machine, which are, as has been explained, between the gibs and in the cross-head collar. Evidently the most strain will come upon the point of support inthe cross-head, that being the nearer of the two to the rock. Now, the cross-head is guided by the slides Q, and is altogether independent ofthe pistonrod with reference to transverse strain or motion, because of the peculiarity ot' their attachment already described. It has been customary to have the two points of `support ofthe drill at the two ends of the piston-rod, or to have the drill slide through holes in stationary blocks. In the rst case, the whole strain is thrown upon the piston rods and their packing-boxes, causing serious wear, and thereby considerable leakage between them. In the second case, the arrangement is awkward, and the drill, if unfinished,

is likely to soon wear the hole so that it shall run too loosely init to be guided with any precision. The cross-head, being held in the slides, cannot partake of the rotary motion given to the piston-rod and drill. For this reason the joint between the rod and head is made so as to allow them to turn upon each other, and the collar is so applied to, as to be capable of turning inthe cross-head. It may, however, be preferred to have the cross-headin thei'orm ofa piston running in a cylinder instead of upon slides such as represented. In that ease it may rotate with the piston and drill, and the collar in;the cross-head be dispensed with. lt' care is taken to make the cross-head slides exactly in line with the piston, it will not be necessary to provide for freedom of transverse motion between the cross-head and piston-rod, since the cross-head, even when subjected to transverse strain, will be kept by its own guides in line with the piston and no strain be thrown upon the latter.

In order to check the motion of the piston at the end of the stroke within the narrowest convenient limits, it has been not uncommon to allow the piston to pass the port by which the compressed air has been already admit-ted to the cylinder, and thus coniine the compressed air without opportunity to escape between the piston and cylinder head. The air so confined oii'ers a constantly-increasing resistance to the motion of the piston, thus acting to stop it sooner than it' its initial pressnre in the cylinder simply had been exerted. There is, however, the objection to running the piston-packing over the port-that is, it

.the cylinder through the port r.

is likely to become in this way badly'worn or cut-and should there be Water coming over s compressiom) it would, when brought between the moving piston and the cylinder-head without chance of escape through the port, transmit the full blow of the piston to the cylinderhead. Now, in order to avoid the necessity ot' ruiming the packing over the ports to get the cushioning required, the piston-head projects at each end the desired length beyond the packing which is on the face b4 b5.

The arrangement made for keeping the water from the cushioning-spaces requires for its proper action that the machine should be used with the openings r r of the ports into the cylinder on the lowest side of the cylinder, and the end of the cylindernear the port r not much lower than the other. The ends of the piston projecting beyond the packing are made of reduced diameter, and the bore from a. a', made to tit one end and the hollow in the cylinder-head A the other, as already 'explained. It will be seen that if any water is thrown upon the end of the piston through the port r it will run oft into the annular space around b b, which space is always open to the port, while the cushioning is upon the area b5 b5 of the piston. If any water comes through the port i", it will settle in the annular space between the piston-rod C and the small part of the cylinder at a a', and from it be driven back through the port when the piston strikes it. While, as has been said, this arrangement for the. escape of 'water will not act to advantage in some positions of the machine, it yet has no disadvantages even in these positions over the ordinary' plan, and the niachine will be used in all positions, freeing it self in theproper way, as above explained, when it can, and choking with water like those heretofore used when it must.

It has been explained that the slide-l ar V has a reciprocating motion With the piston. As the engine makes its stroke from the end near which it is represented in the drawings, the inclined parte ot' the slot in the bar strikes upon the piu in the valve stem and m'oves vit toward the valvechest, thereby opening the main valve so as to let the compressed air into 0n the return-stroke the incline V2 strikes the pin, mo ving the ValVehalf-'Way over and cutting oft' the compressed air, and yet not opening the exhaust. The longer edge of the pin U (see Figs. 9, 10, and l1) strikes upon the side e of the ledge v fv, by which it is kept from going too far over. When the ledge has passed from behind the pin U, the latter is struck by the incline V3, and the valve is moved over and opens the exhaust. The stroke of the piston is now changed, and, on returning, the ledge on the slide-bar passes just clear of the end of the pin U', the end of the longer side ot' which comes opposite the narrowest partot the ledge. Although the slide bar moves the its beveled end. This uncatching ofthe spring being fairly accomplished, the incline in the bar reaches the pin U', and through it moves the valve-stem and valve and the yoke, carrying the end of the yoke oft' the bar, allowing the spring to catch upon the pin in the new position of the valve. i

I doV not claim a cylinder, a piston, a tubu lar piston rod, (extending in opposite directions from the piston and entirely through both ends of the cylinder,) a set of gibs at or near each or either end of such. piston-rod, and mechanism for operating such gibs, this latter mechanism being set in action by the pressure of the air in the cylinder, and its purpose being to cause the sets of gibs to alternately seize and release the drill, in order to enable it to be operated by the piston during its longitudinal movements. Nor do I claim the valvechest, valve, and air-passages, as arranged and applied to the cylinder A, in manner sub' stantially as hereinbcfore described.

What I claim as my invention, andvdesire to secure by Letters Patent, is-

1. The combination and a1 rangement of the piston E, the openings o c', the piston-rod F, its packing Dit, the piston Gr, and the openings d with the cylinders K A, the tubular pistonrods G D, and the hollow cones I and L and the gibs J J, the whole being constructed in manner and so as to operate substantially as described.

2. The combination of the cross-head Q and the slides Q" (constructed and operating substantially as described) with the drill N and the 'tubular pistou G, and the combination of the collar Q therewith, the same being for the purpose speciiied.

3. The connection of the cross-head Q with the pistonsrod C in such manner that there may be a freedom of transverse and rotary motion with reference to one another, as and l for the purpose hereinbefore described.

4. The combination of the cushioning-space i X and the piston-extension b 11', or their equivalents, with the port r', arranged in the cylinder and with reference to such space,` substantially in manneras specified.

5. The construction of the cylinder A with the reduction of bore, as shown at a a', and the piston B, with the part b b', to operate in such reduction, the port r being disposed with reference thereto, as specified.

6. rEhe combination of the spring M, the nut H, and the series ot' uotches hh, or their equiva lents, with the hollow cone I, the same being substantially as and for the purpose described.

7. The combination of the seglnents P P' ot' a conical ring, the cylinders p p and 1)19", the ring p4, and the hollow cones in the head A and the follower A", the whole being substantially as and for the purposes set forth.

8. The combination ofthe spring W, the pin u, and the yoke U with the valve-stem U and the slidebar V, constructed, arranged, and operating substantially as described.

9. The combination as well as the arrange ment of the piston E, the piston-rod F, its packing bt, and the piston G.

10. 'lhe combination of the openings c c and d, the piston-rods D F, (arranged with a tubular space between them,) the pistons E and G, and the packing bt, the whole being arranged substantially as described.

JAMES D. BUTLER.

Witnesses:

It. H. EDDY, F. P. HALE, Jr. 

